Valve apparatus having leak-detecting means

ABSTRACT

Apparatus making use of at least one main flow control valve and having means for determining whether or not the valve is leaking. The valve employs a sealing assembly which seals with respect to the valve working surface of the valve member (e.g., gate) on two spaced concentric areas. Duct means serves to establish communication between the space between the sealing areas and the exterior of the valve. In the event of leakage past the sealing assembly, it can be detected by noting any discharge of fluid through the duct means to the exterior of the valve. In one embodiment the leakage is noted by opening a vent valve adjacent the main valve. In another embodiment the valve can be checked for leakage at a remote station.

United States Patent Grove et al.

Feb. 8, 1972 Inventors: Marvin H. Grove; Kee W. Kim; Lyle R.

Van Arsdale, all of Houston, Tex.

Assignee: M 8: J Valve Company, Houston, Tex.

Filed: Mar. 19, 1970 Appl. No.: 21,074

References Cited UNITED STATES PATENTS 3,512,546 5/1970 King ..137/3 123,398,761 8/1968 Grove et al. ...l37/3l2 3 ,050,077 8/1962 Wheatley137/3 12 Primary EraminerM. Cary Nelson I Assistant Examiner-RichardGerard Attorney-Flehr, I-Iohbach, Test, Albritton and Herbert [57]ABSTRACT Apparatus making use of at least one main flow control valveand having means for determining whether or not the valve is leaking.The valve employs a sealing assembly which seals with respect to thevalve working surface of the valve member (e.g., gate) on two spacedconcentric areas. Duct means serves to establish communication betweenthe space between the sealing areas and the exterior of the valve. Inthe event of leakage past the sealing assembly, it can be detected bynoting any discharge of fluid through the duct means to the exterior ofthe valve. In one embodiment the leakage is noted by opening a ventvalve adjacent the main valve. In another embodiment the valve can bechecked for leakage at a remote station.

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ATTORNEYS FIG. 2

BACKGROUND OF THE INVENTION This invention relates generally to valveapparatus for controlling the flow ofvarious fluids, and particularly toapparatus of this kind which is provided with means for detecting valveleakage.

In various industrial and pipe line systems where valves are installedto control fluid flow, it is important to provide a tight shutoff and beable to check a particular valve or group of valves to determine if anyleakage is occurring. By way of example, meter proving systems commonlyemploy valves for controlling the metering cycle. Any leakage past suchvalves seriously interferes with metering accuracy. Assuming that thevalves employed are of the gate type and are provided with sealingassemblies on the upstream and downstream sides of the gate, it ispossible to check leakage by opening a valve connected to the body spaceto vent the body to atmospheric pressure. If fluid continues to flowthrough the valve body after venting a leakage is indicated. A leakdetector which involves venting the body of the valve to atmosphericpressure is disclosed and claimed in U.S. Pat. No. 3,398,761.

One limiting feature leak detectors of the type disclosed in U.S. Pat.No. 3,398,761 is that they detect leakage only past the upstream sealingassembly, irrespective of whether or not there is any leakage past thedownstream sealing assembly. Assuming that the body space of the valveis closed, leakage must occur past both the upstream and downstreamsealing as semblies before the valve is actually leaking fluid from theupstream to the downstrearn'side.

Another objection to leak detecting means of the type described in U.S.Pat. No. 3,398,761 is that when the small vent valve connected to thebody space is opened, a substantial amount of fluid may be dischargedbefore the pressure of the body space is reduced to atmospheric. Also,if there is substantial volume of leakage past the upstream sealingmeans, a relatively large amount of fluid may be discharged from thebody space before the operator is full/ aware of the leaky condition.

SUMMARY THE INVENTION AND OBJECTS It is an object of the presentinvention to provide valve apparatus having leak detecting means whichcan be used to determine whether or not the valve is leaking to thedownstream side.

Another object of the invention is to provide apparatus of the abovecharacter which under normal conditions will involve the discharge ofonly relatively small amounts of fluid in checking the valve todetermine leakage.

Another object of the invention is to provide apparatus of the abovecharacter which facilitates operation from a remote station.

In general, the present invention consists of a valve body having flowpassages for connection with associated piping and a valve member withinthe body movable between open and closed positions relative to thepassages. A sealing means surrounds at least one of the flow passagesand serves to form a fluidtight seal between the body and the adjacentvalve working surface of the valve member. The sealing means is anannular sealing assembly comprising a rigid seat ring carried by thebody and sealing means of resilient material carried by one end face ofthe seat ring. The sealing means is characterized by having spacedconcentric areas of sealing contact with the valve working surface ofthe valve member. Duct means is provided in both the seat ring and thebody for establishing fluid communication between the space between thesealing areas and the exterior of the valve. The duct means exterior ofthe valve is connected to a vent valve to enable venting the space toatmospheric pressure. In one embodiment the vent valve is operated froma remote station and this station also has means which indicates abuildup of pressure in said space after the vent valve has been closed.

BRIEF DESCRIPTION OF THE FIGURES FIG. 1 is a side elevational viewpartly in section illustrating a valve of the type with which thepresent invention may be employed.

FIG. 2 is a detail in section illustrating portions of the sealingassemblies on both the upstream and downstream sides of the valve andthe ducts communicating with the same.

FIG. 3 is an enlarged view in section illustrating a suitableconstruction for the assembly which makes sealing contact with the valvemember.

FIG. 4 is a view like FIG. 3 but showing sealing contact with the valvegate.

FIG. 5 is a schematic view illustrating'electrically operated ventvalves and pressure switches connected between the valve and a remotestation for leakage indication.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 of the drawingillustrates a gate valve suitable for use in the present invention. Thisgate consists of a body 10 which can be fabricated as by wel;ing fromstructural steel shapes (e.g., steel plate), with the end walls 11 ofthe body provided with flow passages 12 which communicate with thepiping 13. The gate 14 within the body may be operated manually betweenfull open and closed positions, or may be connected to suitable poweroperating means such as a hydraulic operator 16. The body space 17within which the gate 14 is disposed is closed by the bottom closureplate 18 and the upper bonnet assembly 19. The latter provides a sealabout the operating rod (not shown). A sealing assembly 21 is carried byone of the end walls and establishes a seal between the body and theadjacent valve working surface 22 of the gate. It is assumed in thisinstance that at least one such assembly is on the upstream side of thegate. It is common practice to provide sealing assemblies upon both theupstream and downstream sides.

To carry out the present invention a sealing assembly is employed whichestablishes sealing contact with the valve working surface of the gatealong two concentric areas. Such a sealing assembly is disclosed incopending application Ser. No. 17,365 filed Mar. 9, 1970 and may beconstructed as shown in FIGS. 2 and 3. In this-instance each of the twoassemblies consists of a rigid metal seat ring 26 which has its one endface 27 is close proximity with the adjacent valve working surface 22 ofthe gate. This ring carries on assembly 28 like that shown in FIG. 3,which establishes fluidtight contacts with the valve working surface.The extension portion 29 of the seat ring is machined to provide theexterior cylindrical periphery 31 and grooves for accommodating the sealrings 32 of the resilient.

O-ring type. The body is machined to provide the recess 33 foraccommodating the seat ring. This recessing provides a cylindricalperipheral surface 34 which is slightly larger in diameter than thecylindrical surface 31 of the seat ring, and which is contacted by theO-rings 32. A plurality of circumferentially spaced compression springs34 serve to urge the seat ring toward the gate.

The assembly 28 shown in FIG. 3 is substantially the same as disclosedin said copending application Ser. No. 17,365 except for the duct meansto be presently described. Thus the seat ring is provided with anannular cavity 36 which is defined by the inner and outer peripheralsurfaces 37 and 38 and the bottom surface 39. The surfaces 37 and 38 insection are convergent toward the end of the seat ring as illustrated.Within the recess 36 there is a ring 41 which is made of relatively hardresilient material like nylon. Also there are members 42 and 43 whichare made of more resilient material, such as suitable synthetic rubber.The members 42 and 43 are normally highly compressed, this beingaccomplished by the method of assembly. As explained in said applicationSer. No. 17,365, the members 42 and 43 may be resilient rubber bands orstrips which are applied to the peripheral surfaces 37 and 38 withsuitable fluid cement before the nylon ring 41 is inserted into therecess 36. Thereafter additional cement is applied to the surfaces ofmembers 42 and 43, the nylon ring is pressed into the recess betweenthese members whereby the members 42 and 43 are compressed and distortedto somewhat the configuration illustrated in FIG. 3. Thereafter, excessrubber is trimmed from members 42 and 43 and the face of the nylon ring41 is machined as illustrated. This then provides resilient annularsealing faces 44 and 45 and adjacent areas 46 and 47 on the nylon ring41.v Areas 46 and 47 are shown separated by the annular groove 48.Normally faces 44 and 45 are in a common plane that is offset somewhatbeyond the plane of the surfaces 46 and 47 as illustrated in FIG. 3.When pressed against a gate as in FIG. 4, the faces 44 and 45 arecompressed a limited amount to bring them into coincidence with theplane of faces 46 and 47, and with the surfaces 44 and 45 establishingfluidtight engagement with the valve working surface. It will be evidentthat with this assembly, sealing contact with the valve working surfaceis established on two concentric areas represented by the surfaces 44and 45. The space between surfaces 44 and 45 (represented by groove 48),or in other words the space between the two areas of sealing contact, isin efiect isolated from both the upstream line pressure and the pressurewithin the body space.

As shown particularly in FIG. 2, duct means is provided whereby thespace (i.e., groove 48) between to two sealing areas described above canbe placed in communication with the exterior of the valve. Referringagain to FIG. 2 the nylon ring 41 is provided with one or more ducts 51which are in communication with groove 48 and one or more ducts 52 inthe metal seat ring 29. Duct 52 connects with one or more radiallyextending ducts 53 which communicate with the annular space 54 betweenthe two O-ring seals 32. A duct 56 in the adjacent side portion of thebody communicates between the space 54 and the exterior fitting 57.

It is a characteristic of the sealing assembly described above that onthe upstream side a fluidtight seal is established on the inner sealingarea, or in other words, the sealing area of the smaller diameter. Thisassumes that a pressure differential exists between the upstream linepressure and the body space. If fluid should leak past this sealingarea, it will leak past the outer sealing area, assuming that thedifferential pressures involved are substantial. However, some pressureis required in the space between to two pressure areas for fluid withinthe space to leak past the outer area. On the downstream side theconditions are reversed. In other words, the pressure holding seal isestablished by the outer sealing area, and if leakage occurs past thisarea, it can leak past the inner area. If on the upstream side theleakage is not excessive, it can flow through the ducts 51, 52, 53 and56 to the exterior of the valve. The same applies to leakage on thedownstream side. Thus the discharge of any fluid to the exterior of thevalve through one of the fitting 57 indicates a leakage past thecorresponding sealing assembly. Normally it is desirable to prevent suchflow of fluid from the upstream sealing assemblies by closing thecorresponding duct 56 and fitting 57. When it is desired to check thevalve to determine if it is leaking, with pressure applied to theupstream side, the duct 56 for the upstream sealing assembly can beopened to observe any discharge of fluid. If no fluid is discharged,other than an initial small amount to reduce the pressure toatmospheric, then the upstream assembly is not leaking. The same testcan be made with respect to the downstream seal. In testing the valve inthis manner for leakage, it is not necessary to vent the body space toatmospheric pressure, as with the prior apparatus previously described.

As shown in FIG. 2, the fittings 57 are provided with small manuallyoperated vent valves 61. Each valve is provided with an operating handle62 for easy operation between open and closed positions. When the valvecorresponding to the up stream side is opened, the relatively smallvolume of space represented by groove 48 between the sealing areas andby the ducts, is quickly vented to atmosphere without the discharge ofany substantial amount of fluid. Thereafter, any further or continueddischarge of fluid indicates leakage.

In addition to employing the construction described above fordetermining leakage, it is possible to employ the ducts for theintroduction of a suitable lubricant. Thus each of the small valves 61can be provided with a lubricant fitting 63 whereby when the valve isopen a lubricant injection gun can be applied to force lubricant underpressure through the ducts and into the groove 48 ring 41. In thisconnection the sealing assembly described is self-relieving with respectto build up of excessive pressure in the space between the two sealingareas. In other words, pressure developed by the introduction oflubricant into the space between the two sealing areas cannot exceed acertain value, because beyond such pressure the lubricant will escapepast the sealing areas.

For remote operation and indication, the arrangement shown in FIG. 5 canbe used. In this instance, the two fittings 57 are connected by tubingor piping 64 and 65 to the solenoid-operated vent valves 66 and 67. Thesolenoid windings are shown connected to a common energizing circuit 68which is controlled by switch 69. The pipes 64 and 65 also connect withthe pressure-operated switches 71 and 72 which have their contactsconnected in series with the detecting circuit 73. This circuit may becontrolled by the switch 74. Suitable indicating means 75, such as asignal lamp, is in series with circuit 73. The switches 69 and 74 andindicating means 75 are located at a remote station. To determine if themain valve is leaking, the operator at the remote station closes theswitch 69 for a short interval to energize the solenoid vent valves 66and 67, whereby the pipes 64 and 65 are vented to atmosphere.Thereafter, switch 69 is opened and switch 74 closed. Ifa buildup ofpressure occurs in both the pipes 64 and 65, both of the pressureswitches 71 and 72 are operated, thus closing their contact to operatethe indicator 75. It will be noted in this connection that with thecontacts of the pressure switches 71 and 72 in series, a leak indicationis not obtained unless there is leakage past both the upstream anddownstream sealing assemblies. Such leakage means that the valve isleaking from the upstream to the downstream side. If only the upstreamsealing assembly is leaking, but the downstream assembly is not leaking,then one of the pressure switches would not be operated, and theindicator 75 would not be energized.

As previously noted the pressure buildup on groove 48 is limited by theinherent self-relieving action. However, the buildup is sufficient foroperating switches 71 and 72.

It will be evident from the foregoing that the present invention has anumber of desirable features. Particularly in determining whether or notthe sealing assemblies are leaking, it is necessary to vent only aminimum amount of fluid to the atmosphere. In other words, it is notnecessary to discharge considerable quantities of fluid from the valvebody. One can make a leakage determination individually with respect tothe upstream and downstream assemblies. Also one can make a leakagedetermination with respect to both the upstream and downstream sides inthe manner described in connection with FIG. 5. Although the inventionis primarily for the purpose of determining possible leakage, it alsoserves to permit application of lubrication to the sealing areas.

The valve described above has sealing assemblies on both the upstreamand downstream sides. Also each assembly has sealing areas which havediameters smaller than the diameter of surface 34. Thus on the upstreamside line pressure urges the assembly toward the gate. Also excessivebody pressure (above line pressure) urges the assembly away from thegate to permit such pressure to be relieved. On the downstream side thesealing assembly takes the thrust of the gate.

In place of two sealing assemblies, the valve may have one sealingassembly on the upstream side, in which event it is desirable toproportion the seat ring whereby the mean diameter of ring 41 issubstantially the same as the diameter of surface 34. This provides asingle assembly which will seal against pressure applied in eitherdirection.

While the invention has been described in connection with a valve of thegate type, it can be employed with other types of valves (e.g., plug,ball, plunger, etc.).

We claim:

1. in valve apparatus, a body having flow passages for connection withassociated piping, a valve member within the body and movable betweenopen and closed positions relative to the passages, said member havingvalve working surfaces, and sealing means surrounding each of thepassages and serving to form fluidtight seals between the body and valveworking surfaces of the valve member on both the upstream and downstreamsides of the valve, each of said means including an annular sealingassembly comprising a seat ring and seal means of resilient materialcarried by one end face of the seat ring, said seal means having spacedconcentric areas of sealing contact with the associated valve workingsurface, duct means in the valve body and the seat rings forestablishing fluid communication between the spaces between the sealingareas on both the upstream-and downstream sides and the exterior of thevalve, electrically operated vent valves connected to each of said ductmeans exterior of the body, each of said valves serving to vent theassociated duct means to the atmosphere or close the same, a pressureoperated electrical switch connected to each of said duct means, anelectrical energizing circuit forthe vent valve extending to a remoteoperating station, switch means at the remote operating station forclosing said energizing circuit to effect conjoint operation of the ventvalves, an indicating circuit extending from the pressure operatedswitches to the remote station, an indicator at the remote stationserving to indicate closing of said indicating circuit, said indicatingcircuit including the contacts of each of said pressure operatedswitches in series whereby a buildup of pressure in the duct means ofboth the upstream and downstream assemblies is required to close saidindicating circuit to effect an indication at the remote station.

2. In valve apparatus, a body having flow passages for connection withassociated piping, a valve member movable within the body between openand closed positions relative to the flow passages, said member having avalve working surface, at least one seat ring movably carried by thebody and surround one of the flow passages, one face of the seat ringbeing disposed adjacent the valve working surface, resilient sealingmeans carried by said seat ring, the seat ring being recessed toaccommodate the sealing means, said sealing means comprising inner andouter concentric and radially spaced annular members made of resilientmaterial and annular means interposed between the resilient membersserving to retain the same on the seat ring with radially spaced edgefaces of the members projecting from said one face of the seat ring forsealing contact with the valve working surface on radially spaced areas,the radially opposed peripheral surfaces of said members being supportedby said annular means whereby the inner resilient member seals againstpressure differential applied from said one flow passage and the outerannular member seals against pressure difierential applied from thespace surrounding the seat ring, said resilient members beingself-relieving with respect to a predetermined pressure in the spacebetween said annular areas which applies pressure differential to one orthe other of the resilient members, said predetermined pressure beingsubstantially less than that of the flow passage fluid pressure, andduct means in the seat ring and in the valve body for establishing fluidconnection with the space between said sealing areas and the exterior ofthe valve.

3. A valve construction as in claim 2 together with a vent valveexterior of the valve-body for maintaining said duct means closed or forventing the same to the atmosphere.

4. Apparatus as in claim 2 together with an electrically operated ventvalve in communication with the exterior end of said duct means andserving to vent said duct means to the atmosphere or to close the same,a pressure operated electrical switch also in communication with saidduct means exterior of the valve and electrical circuitry extending to aremote station, said circuitry including switch means at the remotestation for energizing the vent valve, an indicating circuit connectedto the contacts of the pressure operated switch and ex tendingto theremote station, and an indicator at the remote station in series withsaid last named circuit, said indicating circuit being closed by closureof the contacts of said pressure operated switch to energize theindicating means at the remote station.

5. Apparatus as in claim 2 together with an additional seat ring movablycarried by the body and surrounding the other one of said flow passages,and resilient sealing means carried by said last named seat ring havinga construction as defined for said first named seat ring, duct means inthe last named seat ring and the valve body for establishing fluidconnection with the space between the sealing areas of said secondsealing means and the exterior of the valve, two electrically operatedvent valves exterior of the valve and in communication with the exteriorends of said duct means, said vent valves serving to vent said ductmeans to the atmosphere or close the same, pressure operated electricalswitches also in communication with both said duct means exterior of thevalve, and electrical circuitry extending to a remote operating station,said circuitry including switch means at the remote station forenergizing both of the vent valves, an indicating circuit connected tothe contacts of both of the pressure operated switches and extending tothe remote station, and an indicator at the remote station in serieswith said last-named circuit, said indicating circuit being closed byclosure of the contacts of both of said pressure operated switches toenergize the indicating means at the remote station.

1. In valve apparatus, a body having flow passages for connection withassociated piping, a valve member within the body and movable betweenopen and closed positions relative to the passages, said member havingvalve working surfaces, and sealing means surrounding each of thepassages and serving to form fluidtight seals between the body and valveworking surfaces of the valve member on both the upstream and downstreamsides of the valve, each of said means including an annular sealingassembly comprising a seat ring and seal means of resilient materialcarried by one end face of the seat ring, said seal means having spacedconcentric areas of sealing contact with the associated valve workingsurface, duct means in the valve body and the seat rings forestablishing fluid communication between the spaces between the sealingareas on both the upstream and downstream sides and the exterior of thevalve, electrically operated vent valves connected to each of said ductmeans exterior of the body, each of said valves serving to vent theassociated duct means to the atmosphere or close the same, a pressureoperated electrical switch connected to each of said duct means, anelectrical energizing circuit for the vent valve extending to a remoteoperating station, switch means at the remote operating station forclosing said energizing circuit to effect conjoint operation of the ventvalves, an indicating circuit extending from the pressure operatedswitches to the remote station, an indicator at the remote stationserving to indicate closing of said indicating circuit, said indicatingcircuit including the contacts of each of said pressure operatedswitches in series whereby a buildup of pressure in the duct means ofboth the upstream and downstream assemblies is required to close saidindicating circuit to effect an indication at the remote station.
 2. Invalve apparatus, a body having flow passages for connection withassociated piping, a valve member movable within the body between openand closed positions relative to the flow passages, said member having avalve working surface, at least one seat ring movably carried by thebody and surrounding one of the flow passages, one face of the seat ringbeing disposed adjacent the valve working surface, resilient sealingmeans carried by said seat ring, the seat ring being recessed toaccommodate the sealing means, said sealing means comprising inner andouter concentric and radially spaced annular members made of resilientmaterial and annular means interposed between the resilient membersserving to retain the same on the seat ring with radially spaced edgefaces of the members projecting from said one face of the seat ring forsealing contact with the valve working surface on radially spaced areas,the radially opposed peripheral surfaces of said members being supportedby said annular means whereby the inner resilient member seals againstpressure differential applied from said one flow passage and the outerannular member seals against pressure differential applied from thespace surrounding the seat ring, said resilient members beingself-relieving with respect to a predetermined pressure in the spacebetween said annular areas which applies pressure differential to one orthe other of the resilient members, said predetermined pressure beingsubstantially less than that of the flow passage fluid pressure, andduct means in the seat ring and in the valve body for establishing fluidconnection with the space between said sealing areas and the exterior ofthe valve.
 3. A valve construction as in claim 2 together with a ventvalve exterior of the valve body for maintaining said duct means closedor for venting the same to the atmosphere.
 4. Apparatus as in claim 2together with an electrically operated vent valve in communication withthe exterior end of said duct means and serving to vent said duct meansto the atmosphere or to close the same, a pressure operated electricalswitch also in communication with said duct means exterior of the valveand electrical circuitry extending to a remote station, said circuitryincluding switch means at the remote station for energizing the ventvalve, an indicating circuit connected to the contacts of the pressureoperated switch and extending to the remote station, and an indicator atthe remote station in series with said last named circuit, saidindicating circuit being closed by closure of the contacts of saidpressure operated switch to energize the indicating means at the remotestation.
 5. Apparatus as in claim 2 together with an additional seatring movably carried by the body and surrounding the other one of saidflow passages, and resilient sealing means carried by said last namedseat ring having a construction as defined for said first named seatring, duct means in the last named seat ring and the valve body forestablishing fluid connection with the space between the sealing areasof said second sealing means and the exterior of the valve, twoelectrically operated vent valves exterior of the valve and incommunication with the exterior ends of said duct means, said ventvalves serving to vent said duct means to the atmosphere or close thesame, pressure operated electrical switches also in communication withboth said duct means exterior of the valve, and electrical circuitryextending to a remote operating station, said circuitry including switchmeans at the remote station for energizing both of the vent valves, anindicating circuit connected to the contacts of both of the pressureoperated switches and extending to the remote station, and an indicatorat the remote station in series with said last-named circuit, saidindicating circuit being closed by closure of the contacts of both ofsaid pressure operated switches to energize the indicating means at theremote station.